Polygonatum sibiricum polysaccharides (PSPs) have important biological functions, such as antioxidation, immunomodulatory, and hypolipidemic functions. Different extraction methods have effects on their structures and activities. In this study, six extraction methods, including hot water extraction (HWE), alkali extraction (AAE), ultrasound-assisted extraction (UAE), enzyme-assisted extraction (EAE), microwave-assisted extraction (MAE), and freeze–thaw-assisted extraction (FAE) were used to extract PSPs, and their structure–activity relationships were analyzed. The results showed that all six PSPs had similar functional group compositions, thermal stability, and glycosidic bond compositions. PSP-As (PSPs extracted by AAE) exhibited better rheological properties due to their higher molecular weight (Mw). PSP-Es (PSPs extracted by EAE) and PSP-Fs (PSPs extracted by FAE) had better lipid-lowering activity due to their lower Mw. PSP-Es and PSP-Ms (PSPs extracted by MAE), which do not contain uronic acid and have a moderate Mw, had better 1,1-diphenyl-2-picrylhydrazyl (DPPH)-radical-scavenging activity. On the contrary, PSP-Hs (PSPs extracted by HWE) and PSP-Fs, with the Mw of uronic acid, had the best OH-radical-scavenging activity. The high-Mw PSP-As had the best Fe²⁺-chelating ability. In addition, mannose (Man) may play an important role in the immunomodulatory activity. These results indicate that different extraction methods affect the structure and biological activity of polysaccharides to varying degrees, and these results are helpful for understanding the structure–activity relationship of PSPs.

Hyperlipidemia is a chronic metabolic disease caused by the abnormal metabolism of lipoproteins in the human body. Its main hazard is to accelerate systemic atherosclerosis, which causes cerebrovascular diseases such as coronary heart disease and thrombosis. At the same time, although the current hypolipidemic drugs have a certain therapeutic effect, they have side effects such as liver damage and digestive tract discomfort. Many kinds of polysaccharides from natural resources possess therapeutic effects on hyperlipidemia but still lack a comprehensive understanding. In this paper, the research progress of natural polysaccharides on reducing blood lipids in recent years is reviewed. The pharmacological mechanisms and targets of natural polysaccharides are mainly introduced. The relationship between structure and hypolipidemic activity is also discussed in detail. This review will help to understand the value of polysaccharides in lowering blood lipids and provide guidance for the development and clinical application of new hypolipidemic drugs.

Coriolus is the dried fruiting body of Coriolus versicolor (L. ex Fr.) Quel. C. versicolor (CV) is a worldwide-distributed fungus, which is common and widely used in primitive forests in the northern hemisphere. Polysaccharide, as the main active ingredient in CV, has a variety of biological activities, such as promoting immune function, antivirus, antitumor, anti-diabetes, and so on. However, Coriolus versicolor polysaccharide (CVP) faces the problems of a single extraction method, lack of research on separation and purification, and the research on structural characterization is limited to the primary structure. Furthermore, the existing research results have not been systematically reviewed. Therefore, this paper summarizes the research status of CVP in terms of extraction technology, separation and purification, structural characterization, and pharmacological activity in recent years, in order to provide a theoretical basis for in-depth research, development, and utilization of CVP.

Iron deficiency anemia can lead to a variety of functional disorders, which is one of the highest incidence of nutrient deficiency diseases. The direct addition of iron to food will not only brings difficulties to the production of products, but also brings damages to human body. In recent years, international studies have shown that polysaccharide iron complex (PIC) not only has a variety of pharmacological activities of polysaccharide itself, but also has the function of supplementing iron, so it is a good iron supplement. With the advantages of good solubility, high iron content, low gastrointestinal irritation and high bioavailability, PIC is an effective iron supplement for iron deficiency anemia and has attracted more and more attention. In this paper, the different preparation methods, structural characterization, biological activities and clinical applications of PIC synthesized by natural polysaccharides from plant were reviewed, in order to provide theoretical basis for the development and application of PIC.